What items and equipment should I use for Undyne the Undying?

[Aloe Vera]

Currently, I'm stuck fighting Undyne the Undying. I was having a hard time, so I did a reset to help give myself a break, and to obtain the items I need for when I fight her again.
Usually, I would die when she had somewhere between half her health and one fourth of her health.
But, I'm having a hard time deciding what I should use during the battle.
Any help?

1: Which items?
Currently, the items I'm planning on using are 3 snow pieces and 3 cinnamon bunnies, as both are easy to obtain (on genocide) and heal a considerable amount. What should I use for the other two slots during the battle?
I won't use Sea Teas, because though the speed boost could help for some of the red soul attacks, the amount it heals is pretty bad, and usually the speed boost just stops me from using the pattern that usually works.
I also won't use the Butterscotch Pie. I'm saving that for Sans.

2: What equipment?
Before the reset, I was using the Dusty Tutu and the Ballet Shoes, which worked out pretty well.
But should I use the Old Notebook and Cloudy Glasses? The invinsibility frames could help me out, but I'm also good at taking damage, which is why having the Dusty Tutu and Ballet Shoes may be the better option.

Thanks for the help! I appreciate it lots! :D

[Blueberry Tea (Ruby)]

The best weapon you could use is Ballet Shoes and best armor is Dust Tutu.

As for items, it is a good idea to save Bscotch pie for Sans, and as many snowman pieces as possible if you can.
Cinna bunny is probably your best option for the rest of the slots.

This fight takes a LOT of determination and learning the attacks. You should try to focus more on taking her health down more than healing, but if you do heal then make sure you get the most out of it by checking to see if the amount of health you'll get from the item will go above your HP cap. If it does then don't use it, if it doesn't then you can freely use it if you're low on health or if a difficult attack is coming up.

The good thing is, while this boss may not be as predictable as Sans, most of Undyne the Undying's attacks can be avoided if you know how they work as most are predictable. It helps to aim for the red arrows (especially on the slow spears attack), as they're the ones that'll hit you first. After you put your shield up in front of a red arrow look to see what's the next arrow that'll likely hit you and aim for that, always stay ahead of the game.

Here's a video that showcases all of Undyne's attacks and how to easily avoid them, it should help out a ton with the fight: https://www.youtube.com/watch?v=ntXMwAspzFw

The only other tips I can give is to take frequent breaks (the more frustrated you are, the more likely you are to make stupid mistakes.)
Stay determined, and don't feel bad about dying a lot to this boss, everyone does.
Remember that even if you die, you learn a little more about the fight and you get progressively better, so dying a lot will make things easier for you.
Don't spaz out with your spear blocker, just stay cool and collected, it'll help you a lot more than you might think.

Sorry I can't be much more of help than that, but good luck!